Concrete blocks are a very popular way in which to build walls of buildings and houses. Concrete blocks are typically formed with hollow cores or voids. Concrete block walls are cost-effective and relatively easy to build.
In order to build a concrete block wall, blocks are laid in a number of courses. During the construction of the various courses of blocks, horizontal reinforcement bars are placed along predetermined courses of blocks within the block wall. The horizontal bars require positioning in accordance with the structural requirements of the wall being constructed. Once all of the blocks are laid within the block wall, vertical reinforcement bars are then placed through the block wall. Again, the vertical bars require positioning in accordance with the structural requirements of the wall being constructed. Concrete is then poured into the voids within the block to complete construction of the block wall.
The position of the reinforcement bars within the block wall are dependent upon the structural requirements of the block wall. For example, where there is a side loading on a block wall, the vertical reinforcement bars are generally located non-centrally in the block wall and must be positioned to ensure grout cover is in compliance with industry standard. Similarly, under normal vertical load conditions, the reinforcement bar is located centrally in the block wall.
It is relatively easy to locate the horizontal reinforcement bars in a desired location. This is due mainly to the horizontal reinforcement bars being able to be viewed when they are being laid. However, in order to ensure the vertical reinforcement bars are subsequently located correctly, the horizontal reinforcement bars do require correct location within the recess provided in the top surface of the blocks. Further, there are brackets such as those described in International Patent Application No. PCT/AU2005/001455 which assist in alignment of the horizontal reinforcement bars. However, it is substantially more difficult to correctly align the vertical reinforcement bars in block walls.
The most widely used conventional method in aligning the vertical reinforcement bars has been to leave holes out of the bottom course of blocks so that the vertical reinforcement bars can be manually aligned. Hence, when the vertical reinforcement bar is lowered through the voids in the blocks of the block wall, the vertical bar can be tied in a desired position at the top and the bottom of the block wall.
The problem with this method of aligning the reinforcement bar is that it relies upon a person measuring the distance of the bar from the side wall for each of the vertical bars. This is very time consuming. Further, it also relies upon a person tying the bar which again adds a considerable amount of time in alignment of the vertical bars. It is also a requirement of masonry wall construction that the vertical bars are positioned adjacent to the previously positioned horizontal bars to create a mesh of reinforcement to provide structural strength of the completed wall. It follows then, that if the horizontal reinforcing bars have been incorrectly positioned, then the vertical reinforcing bars will be incorrectly positioned when tied to the horizontal reinforcing bars. Finally, once the vertical bars are properly aligned, the lower course of bricks must be patched for aesthetic purposes and also to prevent concrete from running out of the block wall when the voids of the block wall are filled with concrete.